Will PDF files carry viruses? The answer is yes, but most PDF files do not contain malware. This article will guide you how to identify and clear malicious PDF files to protect your device's security.

How to carry viruses in PDF files?

Malware can penetrate PDF files through a variety of ways:

• Editable content and dynamic elements: Dynamic elements such as editable parts, date and time display and calculation functions of PDF files require code execution, which provides an opportunity for virus installation.
• JavaScript and System Commands: PDF files can contain JavaScript code and execute system commands, which makes it an ideal carrier for malware. Although Adobe has disabled system commands in many PDFs, this only applies to the latest version of Adobe Acrobat and cannot protect you from third-party PDF readers.
• Embedded Multimedia: Embedded multimedia files can contain vulnerabilities that enable attackers to implant malware.
• Plugins: PDF plugins may also run malicious code.

How to check if a PDF file contains a virus?

First, beware of documents of unknown origin. Avoid downloading suspicious files from unknown sites, as infected PDF files are often disguised as free e-books or brochures. Likewise, be careful about email attachments you didn't expect, even if you know the sender (because their email may have been hacked).

Many mail service providers, such as Gmail, scan for malware in attachments. But be aware that sometimes too large files or system failures may cause attachments to be scanned. If you have downloaded a suspicious PDF file, please use a Mac cleaning tool such as CleanMyMac X for system scanning.

Scan your Mac regularly and even the most reliable websites can be attacked. CleanMyMac X's anti-malware module checks for ransomware, adware, and other macOS-specific malware in the system.

How will infected PDF files affect your Mac?

There are many types of PDF viruses:

• PDF Trojan: Steal your information and send it to attackers.
• PDF Malware: Cracking or changing information on your device, such as inserting ads or encrypting information into your browser to ransom (ransomware).
• Downloader: Many PDF viruses are just downloaders that induce you to download the main malicious files.

How to safely download free PDF files from the internet?

Before downloading a file, be sure to consider the following points:

• Download Source: Is it a website or an email attachment? If it is an email attachment, please be aware that the email service provider scans for malware, and who the sender is, and whether you expect to receive this file. If it is a website download, please check the exact address - is it HTTPS and is the domain name reliable?
• File Format: Make sure the file is indeed PDF, not an executable malware file that is masquerading as PDF.
• Reliable Source: If you need a free PDF e-book, use a reputable library or university library to get the files. Project Gutenberg is a well-known online project with over 60,000 free e-books. Buy and download books from reputable sellers like Google Books or Amazon.

Using a VPN can enhance the security of downloading PDF files. A VPN can hide your IP address and encrypt your traffic. If you use public WiFi, a VPN is essential.

Tips to protect your Mac from PDF viruses

In addition to the above methods, you can also:

• Keep the software updated.
• Protect your password and other sensitive information.
• Keep your internet connection secure and private.
• Check and turn off unsafe settings on your Mac regularly, such as AirDrop and remote login. You can use tools such as Pareto Security to assist with inspections.
• Use applications like Secrets to securely store password and credit card information.

You can get the apps mentioned in this article through the Setapp subscription service, such as CleanMyMac X, Pareto Security, Secrets, and ClearVPN.

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